Which of the following is not considered as an organometallic compound?

If $p$-th,$q$-th,and $r$-th terms of a geometric progression are the positive numbers $a, b,$ and $c$ respectively,then the angle between the vectors $(\log a^2) i + (\log b^2) j + (\log c^2) k$ and $(q-r) i + (r-p) j + (p-q) k$ is

The condition for a uniform spherical mass $m$ of radius $r$ to be a black hole is [$G$ = gravitational constant and $c$ = speed of light].

Which of the following has the lowest melting point?

How is red phosphorus obtained from white phosphorus?

Which of the following organisms belongs to the Kingdom $Monera$?